This invention relates to tape measure, particularly a quick rewindable tape measure.
A tape measure has hitherto been made by rotatably placing a reel in an outer case and winding a measuring tape around the reel to house the tape in the case when unused. There has been a tape measure in which a coil spring is provided in the interior of the reel and the measuring tape can be automatically rewound around the reel by the restoring force of the spring. This type of tape measure generally been utilized when the tape has a comparatively short length, particularly less than a length of 10 m. Since it is difficult to rewind the tape by the restoring force of a spring when the measuring tape is of a length from 10 m to 100 m, tape measures have been made so that the measuring tape can be rewound by rotating a handle by hand. Tape measure of this kind were prepared by rotatably placing a reel in a case to enable winding the tape around the reel and also by providing a side of the case with a handle for rotating the reel.
In the case wherein a string is used for measuring the length instead of a tape, twisting of the string causes no trouble when it is rewound. For a device using a string, a quick rewind measure has been prepared hitherto in which the rewind speed was increased to be a few times that of the speed of the handle. In contrast, in the case wherein a tape is used for measuring the length, if the tape is rewound in a high speed, the tape is liable to be twisted. Consequently, a quick rewind tape measure has not been manufactured hitherto.
A kind of the quick rewind tape measure has recently become known. It is disclosed, for example, in Japanese Unexamined Utility Model Publication No. 55-145303. The quick rewind tape measure, however, disclosed in said Publication has a bigger gear having teeth on its outer periphery secured to the handle, and a smaller gear also having teeth on its outer periphery secured to the reel with both gears being engaged. In other words, both gears are nothing but pinions having externally facing gear teeth and are simply engaged in an external relation. As a result, the reel was rotated in the direction reverse to the rotating direction of the handle, and the reel center was greatly distant from the handle center. Thus, when the tape measure is to be rewound, the handle must be rotated in the reverse direction. Rewinding the tape measure could not be smoothly operated. Further, the tape measure itself could not be made compact. Consequently, these were disadvantages of the quick rewind tape measure.